The lead character voiced by Eric Bana is called Chas Hunt, initials C Hunt which is a play on words for an adult word that the Australians have a peculiar fondness for. Goodness knows how they got this past censors.
In the chase scene near the end with the motorbikes, you can see a reference painted on the side of the fuel tank. It says B2TO - Back 2 The Outback.
In the scene where Jackie is being transported out of the zoo the truck's license plate reads "R3M-OVR" or remover referencing its role in the film of removing animals.
Tim Minchin and Harry Cripps previously worked on DreamWorks Animation's canceled Australian movie musical Larrikins.